Re: [PATCH 3/6] nfsd: simplify the delayed disposal list code
From: Chuck Lever III <chuck.lever@oracle.com>
Date: 2023-01-18 19:08:34
On Jan 18, 2023, at 12:31 PM, Jeff Layton [off-list ref] wrote: When queueing a dispose list to the appropriate "freeme" lists, it pointlessly queues the objects one at a time to an intermediate list. Remove a few helpers and just open code a list_move to make it more clear and efficient. Better document the resulting functions with kerneldoc comments.
I'd like to freeze the filecache code until we've sorted out the destroy_deleg_unhashed crashes. Shall I simply maintain 3/6 and 4/6 and any subsequent filecache changes (like my rhltable rewrite) on a topic branch? One good reason to do that is to enable an eventual fix to be backported to stable kernels without also needing to pull in intervening clean-up patches. I've already applied a couple small changes that I would rather wait on for this reason. I might move those over to the topic branch as well... I promise to keep it based on nfsd-next so it makes sense to continue developing filecache work on top of the topic branch. The other patches in this series are sensible clean-ups that I plan to apply for v6.3 if there are no other objections.
quoted hunk ↗ jump to hunk
Signed-off-by: Jeff Layton <jlayton@kernel.org> --- fs/nfsd/filecache.c | 63 +++++++++++++++------------------------------ 1 file changed, 21 insertions(+), 42 deletions(-)diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index 58ac93e7e680..a2bc4bd90b9a 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c@@ -513,49 +513,25 @@ nfsd_file_dispose_list(struct list_head *dispose)} } -static void -nfsd_file_list_remove_disposal(struct list_head *dst, - struct nfsd_fcache_disposal *l) -{ - spin_lock(&l->lock); - list_splice_init(&l->freeme, dst); - spin_unlock(&l->lock); -} - -static void -nfsd_file_list_add_disposal(struct list_head *files, struct net *net) -{ - struct nfsd_net *nn = net_generic(net, nfsd_net_id); - struct nfsd_fcache_disposal *l = nn->fcache_disposal; - - spin_lock(&l->lock); - list_splice_tail_init(files, &l->freeme); - spin_unlock(&l->lock); - queue_work(nfsd_filecache_wq, &l->work); -} - -static void -nfsd_file_list_add_pernet(struct list_head *dst, struct list_head *src, - struct net *net) -{ - struct nfsd_file *nf, *tmp; - - list_for_each_entry_safe(nf, tmp, src, nf_lru) { - if (nf->nf_net == net) - list_move_tail(&nf->nf_lru, dst); - } -} - +/** + * nfsd_file_dispose_list_delayed - move list of dead files to net's freeme list + * @dispose: list of nfsd_files to be disposed + * + * Transfers each file to the "freeme" list for its nfsd_net, to eventually + * be disposed of by the per-net garbage collector. + */ static void nfsd_file_dispose_list_delayed(struct list_head *dispose) { - LIST_HEAD(list); - struct nfsd_file *nf; - while(!list_empty(dispose)) { - nf = list_first_entry(dispose, struct nfsd_file, nf_lru); - nfsd_file_list_add_pernet(&list, dispose, nf->nf_net); - nfsd_file_list_add_disposal(&list, nf->nf_net); + struct nfsd_file *nf = list_first_entry(dispose, + struct nfsd_file, nf_lru); + struct nfsd_net *nn = net_generic(nf->nf_net, nfsd_net_id); + struct nfsd_fcache_disposal *l = nn->fcache_disposal; + + spin_lock(&l->lock); + list_move_tail(&nf->nf_lru, &l->freeme); + spin_unlock(&l->lock); } }@@ -765,8 +741,8 @@ nfsd_file_close_inode_sync(struct inode *inode) * nfsd_file_delayed_close - close unused nfsd_files * @work: dummy * - * Walk the LRU list and destroy any entries that have not been used since - * the last scan. + * Scrape the freeme list for this nfsd_net, and then dispose of them + * all. */static void nfsd_file_delayed_close(struct work_struct *work)@@ -775,7 +751,10 @@ nfsd_file_delayed_close(struct work_struct *work)struct nfsd_fcache_disposal *l = container_of(work, struct nfsd_fcache_disposal, work); - nfsd_file_list_remove_disposal(&head, l); + spin_lock(&l->lock); + list_splice_init(&l->freeme, &head); + spin_unlock(&l->lock); + nfsd_file_dispose_list(&head); } -- 2.39.0
-- Chuck Lever